She opened an ordinary can of tuna, not even imagining the terror she would find inside

The woman was horrified at what she discovered inside the can she had been about to tip onto her children's plates.

Zoe Butler had been opening a can of tuna to feed her children lunch when she came across a disturbing discovery inside the can that made her start.

As reported by World of Wonder, Butler, from the United Kingdom, was opening the innocent looking can of Princess Tuna Chunks, and when she lifted the lid, saw a strange creature staring straight at her from inside.

She immediately snapped a photo of the creature, and took to social media to ask for advice on what on earth it was that was staring at her.

She tweeted: “Can you tell me what this is? Nearly fed this to my children!!”

Some people were quick to respond, suggesting that perhaps it was the severed head of a crab or a shrimp.

"I’m going with inter-dimensional sludge demon come to pillage our towns and plunder our women," suggested World of Wonder.

But what the creature actually is is a parasitic crustacean found in the mouths of fish, called Cymothoa exigua, or tongue-eating louse in layman's terms.

While this sounds incredibly gruesome, it's not quite 100 percent accurate to what the parasite actually does.

It doesn't actually eat the tongue of the fish, rather it destroys it. The parasite does this by extracting the blood from the tongue by digging it's claws in. The tongue essentially dies as it atrophies.

The parasite then takes the place of the fish's tongue, by attaching its body to the stub of the tongue. It does not appear to cause any other harm to the fish. It simply lives off the blood and mucus of the host fish.

Normally these parasites inhabit the bodies of smaller fish than tuna, and it is speculated that the tuna had eaten the parasite's host fish just minutes before it was dragged from the water, chopped up, and jammed into a tuna can.